A variety of packers are used in wellbores to isolate specific wellbore regions. A packer is delivered downhole on a tubing string and a packer sealing element is expanded against the surrounding wellbore wall to isolate a region of the wellbore. Often, two or more packers can be used to isolate one or more regions in a variety of well related applications, including production applications, service applications and testing applications.
In some applications, packers are used to isolate regions for collection of formation fluids. For example, a straddle packer can be used to isolate a specific region of the wellbore to allow collection of fluids. A straddle packer uses a dual packer configuration in which fluids are collected between two separate packers. The dual packer configuration, however, is susceptible to mechanical stresses which limit the expansion ratio and the drawdown pressure differential that can be employed.